Stent system with hydrodynamic monitoring

Abstract

A stent and stent system includes hydrodynamic monitoring. The cradle may have an integrated inductive receiver and an integrated capacitor to facilitate hydrodynamic monitoring. The stent may include layers as a continuous sinusoid. The stent system may also include a transceiver including a processor and an inductive transmitter for coupling to the inductive receiver of the stent. The control unit monitors the frequency of the impedance change at the inductive receiver and determines the fluid pressure and / or flow rate based on the feedback signal.

Description

Technical Field

[0001] This technology relates to a stent system with hydrodynamic monitoring, such as a vascular stent system with hemodynamic monitoring. Background Technology

[0002] Stents are used to open and / or maintain the patency of body cavities. Cardiovascular stents (e.g., coronary stents) are widely used to treat vascular occlusion caused by plaque or lesions in the blood vessels. A stent opens the blood vessel and restores blood flow.

[0003] One problem with using stents is the occurrence of restenosis and target lesion revascularization. Developing a system to monitor blood flow through the implanted stent to detect restenosis, thrombosis, or delayed reendothelialization would be advantageous. Attempts have been made to couple pressure sensors directly to the stent, but with limited success. The drawbacks of such systems are a lack of robustness, stability, and manufacturability. Summary of the Invention

[0004] The present disclosure relates in general to a stent system with hemodynamic monitoring, wherein the stent of the system is formed as a continuous sine curve serving as an antenna (sensor receiver) and / or the stent includes an integrated capacitor for pressure sensing.

[0005] In one aspect, this disclosure provides a stent configured for hydrodynamic monitoring. The stent includes a stent body designed and configured for insertion into a body cavity of a subject. The stent body includes an inner conductive layer, an outer conductive layer, and an insulating layer located between the inner and outer conductive layers. The inner and outer conductive layers, together with the insulating layer, form a capacitor for use in hydrodynamic monitoring.

[0006] In another aspect, this disclosure provides a stent system configured for hydrodynamic monitoring. The stent system includes: a stent configured for implantation into a body cavity of a subject; and a transceiver including a sensor transmitter and a control unit. The stent includes stent wires comprising a conductive layer shaped as a continuous sine wave to form a sensor receiver. The sensor transmitter of the transceiver is configured to be inductively coupled to the sensor receiver to induce a current within the stent wires.

[0007] In another aspect, this disclosure provides a stent configured for hydrodynamic monitoring. The stent includes a stent body designed and configured for insertion into a body cavity of a subject. The stent body integrally forms a sensor and a capacitor, wherein the sensor and the capacitor form an LRC circuit.

[0008] Details of one or more aspects of this disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the technology described in this disclosure will be apparent from the description, drawings, and claims. Attached Figure Description

[0009] Figure 1 This is a conceptual diagram of the stent system disclosed herein, illustrating a system used with a patient.

[0010] Figure 2 This is a side front view of the support system's bracket.

[0011] Figure 3 It is an enlarged sinusoidal portion of the support conductors of the support, and also includes an enlarged detailed cross-section showing the support conductors of its layers.

[0012] Figure 4 This is a circuit diagram of a transceiver circuit and a support circuit that are inductively coupled to each other.

[0013] Figure 5 This is a side front view of another embodiment of the bracket, which includes a separate sensor coupled thereto.

[0014] Figure 6 yes Figure 5 The circuit diagram of the bracket in the middle.

[0015] Figure 7 yes Figure 5 A schematic diagram of a stent implanted in a blood vessel and coupled to a transceiver. Detailed Implementation

[0016] This specification relates to a stent system for fluid dynamic sensing within a body cavity, such as via capacitive pressure sensing. In one or more embodiments, a continuous sinusoidal conductor of the stent in this system serves as a sensor receiver or coil (generally, an antenna), which is inductively coupled to a sensor transmitter (inductor coil) to simultaneously sense alternating current in the stent and provide signal feedback for determining fluid pressure and / or flow velocity within the stent. In one or more embodiments, the stent of the system includes stent conductors having multiple layers, including conductive layers separated by an insulator (i.e., a dielectric), thereby providing the stent with an integrally formed sensor receiver for wireless power supply and an integrally formed capacitor for use in fluid pressure sensing.

[0017] refer to Figure 1A first embodiment of the stent system, generally indicated by reference numeral 10, is configured for intracavitary hydrodynamic sensing, such as changes in fluid pressure and / or flow rate. The illustrated stent system includes a vascular stent, typically indicated by 12, designed and constructed to restore / increase / maintain the patency of a blood vessel (e.g., a coronary artery), such as during or after angioplasty or other interventional cardiology procedures. The stent 12 is configured to expand within the vessel and approximate the lesion. In other examples, the stent may be configured as a graft (including fabric attached to the stent) to redirect blood flow to treat an aneurysms (e.g., aortic stent grafts) or for other treatments. In some embodiments, the stent may or may not be expandable and may be configured for other treatments.

[0018] The illustrated stent system 10 is configured to perform hemodynamic sensing (e.g., changes in blood pressure) within the stent 12 after implantation, which can indicate restenosis or other potential diagnoses. For example, an increase in blood pressure indicates narrowing of the vessel (e.g., restenosis). Hemodynamic sensing can be real-time to provide feedback related to the patency of the vessel in which the stent 12 is implanted. This specification can be combined with or used with other types of stents for other body cavities to assess the hydrodynamic properties of the body cavity, which can be analyzed for the treatment and / or diagnosis of patients. Figure 1 and Figure 2 In this system, stent 12 is a coronary artery stent implanted in the patient's coronary artery, and the system is configured to monitor blood pressure / blood flow within the coronary artery stent.

[0019] Generally, the stent 12 is designed and configured to function as both an antenna (e.g., an inductive receiver and a feedback transmitter), a reference capacitor, and a fluid pressure sensor (i.e., an inductive pressure sensor) to determine changes in pressure (radially outward) or fluid pressure (e.g., blood pressure) within the stent. Reference Figure 3 In one example, the support 12 is formed of multiple layers of single-support wires, which are generally indicated by reference numeral 14. More broadly, the wires 14 define the support body, and in one or more embodiments, the support body may be formed in other ways. Figure 2 As shown, the stent wire 14 is folded or otherwise shaped into a continuous sine wave and then formed (e.g., wound) into a helical coil. Some, all, or no adjacent turns of the helical coil may be joined together (e.g., laser fusion). A suitable manufacturing method for forming this stent body is known in the art as the Continuous Sine Wave Technique (CST). A suitable design and method for shaping the stent wire 14 to form a stent is described in U.S. Patent No. 9,364,351, filed April 23, 2012, the entire contents of which are incorporated herein by reference.

[0020] refer to Figure 3 The illustrated support conductor 14 includes an inner conductive layer 18 and an outer conductive layer 20, respectively radially opposed, and an insulating layer 22 (i.e., a dielectric) radially disposed between the conductive layers. In one embodiment, the inner conductive layer 18 serves as (i.e., forms) an antenna (inductive receiver), and the outer conductive layer 20 serves as a structural layer to realize the support function. Each of the inner conductive layer 18 and the outer conductive layer 20 is of a continuous sine wave shape. The inner conductive layer 18 and the outer conductive layer 20, together with the insulating layer 22, serve as (i.e., form) a capacitor. Thus, the support 12 has an integrated antenna or inductive receiver (e.g., the inner layer 18 forming an inductive coil) and an integrated capacitor (schematically shown and indicated by reference numeral 23). That is, the support 12 serves as an inductor and a capacitor, which together form an LRC circuit (such as... Figure 4 (As illustrated schematically, usually indicated by reference numeral 25 in the accompanying drawings), the reason for which is explained below. Figure 3 As shown, the stent lead 14 also includes an external electrical insulating layer 24 surrounding the external conductive layer 20. The external electrical insulating layer 24 prevents blood and other fluids from contacting the external conductive layer 20. The external electrical insulating layer 24 may be formed of a polymer or other insulating material. In one example, the external electrical insulating layer 24 (or the layer surrounding the electrical insulating layer) may be a drug-eluting layer containing an active agent (e.g., zotamus or everolimus) that is slowly released from the layer to block cell proliferation, as is generally known in the art.

[0021] In a non-limiting example, the inner conductive layer 18 of the support 12 comprises a highly conductive material with no or minimal magnetic properties, such as platinum, gold, silver, copper, iridium, including alloys thereof, or other metals or materials. This layer 18 may be the core of the support wires 14 and may also be radiopaque, allowing it to be visible under fluorescent light. An insulating layer 22 surrounds the inner conductive layer 18. This insulating layer 22 may comprise a polymer (e.g., nylon), a ceramic (e.g., tungsten carbide), or other insulating material suitable for use as a dielectric layer. The outer conductive layer 20 is the structural layer of the support, providing structure and support for its function as a support. In one example, the outer conductive layer 20 is made of a material and is designed to work with a single-layer support (such as Medtronic's ONYX). TM The outer conductive layer 20 is formed and constructed in a similar manner to the support. The outer conductive layer 20 may be formed of a nickel-cobalt alloy (such as MP35N material), which is a non-magnetic nickel-cobalt alloy with a combination of high tensile strength, suitable corrosion resistance, and toughness. In another embodiment, the materials of the inner layer 18 and the outer layer 20 may be reversed, such that the structural layer 20 is located radially inside another conductive layer.

[0022] In the illustrated embodiment, the stent system 10 also includes an external transceiver, typically indicated by reference numeral 30, configured to wirelessly communicate with the stent circuitry 25 from outside the patient's body. The transceiver 30 may be portable or non-portable. The transceiver 30 is also configured to wirelessly transmit power to the stent 12 via inductive coupling (i.e., inductive power transmission). Specifically, the external transceiver 16 includes a transmitter coil 34 (i.e., an inductive transmitter) selectively magnetically coupled to an inductive receiver (antenna) 18 of the stent 12. An alternating current (AC) applied to the transmitter coil 34 generates an oscillating magnetic field. This magnetic field passes through the inductive receiver 18, where it induces an alternating EMF (voltage), which generates an alternating current traveling through the stent circuitry 25. The stent circuitry 25 has a specific resonant frequency that presents a measurable change to the inductive receiver / antenna coil 18 in a magnetically coupled impedance load. The resonant frequency is a function of the inductance of the sensor 18 of the stent 12 and the capacitance of the capacitor 23 of the stent; when the fluid pressure inside the stent changes, the inductance will change in response to vasoconstriction, and the resonant frequency (as a function of inductance and capacitance) will also change.

[0023] Control unit 40 (e.g., a processor and memory having computer-readable instructions) is configured to monitor the frequency of impedance changes at inductive receiver 18 to determine blood pressure within stent 12. Blood flow through stent 12 (i.e., an indication of reduced blood flow) can be inferred by control unit 40 or other processing units using calculated blood pressure. Control unit 40 can also control the power (e.g., alternating current) applied to inductive transmitter 34. Generally, control unit 40 can be used as a network analyzer. Control unit 40 may be part of transceiver 30 and is contained within portable housing 44 together with inductive transmitter 34, such as... Figure 1 As illustrated. The portable casing 44 can be worn by the patient, such as... Figure 1 As shown, the housing is appropriately positioned close to the bracket 12 to achieve inductive coupling between the inductive transmitter 34 and the inductive receiver 18, respectively. Data (e.g., impedance signals and / or pressure / flow data interpreted based on impedance signals) can be wirelessly transmitted to another device, such as a mobile device 46 (e.g., a smartphone or tablet). The mobile device 46 can perform additional signal processing. Data can be transmitted from the mobile device to a remote healthcare server 48. Additional signal processing can be performed at the healthcare server.

[0024] In an exemplary user, stent 12 is implanted in the patient's vascular system, such as in an artery or vein (e.g., a coronary artery). Stent 12 may be delivered to the lesion via a balloon catheter, thereby expanding the stent by inflating the balloon. Stent 12 may be implanted during or after an angioplasty procedure, the techniques of which are well known in the art. Typically, even when using drug-eluting stents during percutaneous coronary intervention, patients are prescribed dual antiplatelet therapy (DAPT; e.g., aspirin and a P2Y12 inhibitor) to prevent stent restenosis. Currently, patients maintain DAPT for at least 6 to 12 months, thus facing the risk of serious complications such as internal bleeding. After implantation, patients can use stent system 10 to monitor the stent's pressure and / or flow characteristics to detect restenosis, thrombosis, or delayed reendothelialization. This diagnosis and / or data is communicated to healthcare professionals to assess the patient's recovery status and help determine further treatment. For example, if sufficient reendothelialization is determined to have occurred, healthcare professionals can have the patient discontinue DAPT, thereby reducing the risks associated with DAPT. Similarly, if stent restenosis is determined to have occurred, healthcare professionals can intervene early to perform patient follow-up, where further examinations are conducted to assess the risk of such complications. Furthermore, it is believed that early diagnosis using this invention can be made before the patient begins to experience symptoms of restenosis, such as pain.

[0025] refer to Figures 5 to 7In another embodiment, the support, generally indicated by reference numeral 112, does not include a support conductor 14 with an integrated capacitor 23 formed by an inner conductive layer 18 and an outer conductive layer 20, and a dielectric 22 disposed between the inner and outer conductive layers. Instead, the support 112 includes a structured single continuous sinusoidal conductor 114 formed by a continuous sinusoidal technique (e.g., a nickel-cobalt alloy such as MP35N) and one or more individual pressure sensors 123 (e.g., capacitive pressure sensors) electrically coupled to the support conductor 114. (The support conductor 114 may also have a drug elution layer or additional layer.) In another embodiment, the support conductor 14 may be used in conjunction with one or more pressure sensors 123. The same transceiver 30 described above may be used with the support 112. In this embodiment, the sinusoidal conductor 114 serves as an antenna (inductive receiver) capable of coupling to a transmitter coil 34 and operates in the same manner as the antenna in the previous embodiment. In one example, two or more sensors 123 are electrically coupled to stent leads 114 to power the sensors and monitor two or more blood pressure readings along stent 112. Sensors 123 may be spaced apart from each other along stent 112. Sensors 123 may be coupled to stent leads 114 using a biocompatible polymer adhesive instead of soldering to maintain stent and circuit integrity. Sensors 123 may be disposed within or outside the coverage area of ​​the stent body. An exemplary sensor 123 may be a thin strip (polymer or metal) with a thickness of 20 μm to 30 μm. Suitable sensors are also available from Murata Manufacturing, Co. A microprocessor 131 may also be coupled to stent leads 114.

[0026] This embodiment offers numerous advantages over known devices. Utilizing a stent manufactured using CST (where the stent leads are formed as a continuous sine curve) eliminates the need for additional stent laser cutting, electroplating, and stencil patterning to achieve commercially available structures with high conductivity. The stent's structure, specifically its structural layers, is easily implemented as an antenna. Furthermore, the described stent embodiment, including an integrated capacitor for pressure sensing, provides advantages over devices that incorporate separate sensors onto the stent, as taught in the prior art. Individual sensors are difficult to apply to stents, and these sensors can be prone to failure. For example, such sensors may be damaged during stent coiling or implantation. This stent with an integrated capacitor is more robust and less prone to failure.

[0027] The present invention may also be described with reference to the following numbered paragraphs: 1. A support configured for fluid dynamics monitoring, the support comprising: A stent body, designed and configured to be inserted into a body cavity of a subject, the stent body comprising: Internal conductive layer External conductive layer, and An insulating layer is located between the inner conductive layer and the outer conductive layer. The inner conductive layer, the outer conductive layer, and the insulating layer together form a capacitor for use in fluid dynamics monitoring.

[0028] 2. The bracket according to paragraph 1, wherein one of the inner conductive layer and the outer conductive layer forms a sensor receiver, wherein the capacitor and the sensor receiver form a bracket circuit, and the sensor receiver is configured to be inductively coupled to a remote inductive transmitter to induce current within the bracket circuit.

[0029] 3. The bracket according to paragraph 2, wherein the inner conductive layer forms the sensor receiver.

[0030] 4. The support according to paragraph 3, wherein the external conductive layer is a structural layer that provides structure and support for the support body to suitably serve as a support.

[0031] 5. The bracket according to any one of paragraphs 1 to 4, wherein the bracket body is formed of bracket conductors that are formed as a continuous sine curve.

[0032] 6. The stent according to any one of paragraphs 1 to 5, wherein the stent body is expandable and configured to conform to the lesion in the blood vessel.

[0033] 7. The bracket according to paragraph 2, wherein the bracket is combined with a portable transceiver, the portable transceiver including the inductive transmitter and a control unit configured to monitor the frequency of impedance changes at the inductive receiver.

[0034] 8. The support according to any one of paragraphs 1 to 7, wherein the inner conductive layer comprises at least one of gold and platinum.

[0035] 9. The bracket according to any one of paragraphs 1 to 8, wherein the outer conductive layer comprises a nickel-cobalt alloy.

[0036] 10. The bracket according to any one of paragraphs 1 to 9, wherein the insulating layer comprises ceramic.

[0037] 11. The support according to any one of paragraphs 1 to 10, wherein the support body further comprises an external electrical insulating layer surrounding the external conductive layer.

[0038] 12. The stent according to paragraph 11, wherein the outer electrical insulating layer comprises a drug elution layer containing an active agent.

[0039] 13. A support system configured for fluid dynamics monitoring, the support system comprising: A stent, configured for implantation into a subject's body cavity, includes a stent lead with a conductive layer shaped as a continuous sinusoidal curve to form a sensor receiver. A portable transceiver includes an inductive transmitter and a control unit, wherein the inductive transmitter is configured to inductively couple with the inductive receiver to induce current within the support conductor.

[0040] 14. The support system according to paragraph 13, wherein the support includes a capacitor electrically coupled to the support wires to form a support circuit.

[0041] 15. The support system according to paragraph 14, wherein the capacitor is integrally formed with the support.

[0042] 16. The support system according to paragraph 15, wherein the support conductor includes another conductive layer and an insulating layer, the insulating layer being radially disposed between the conductive layers to form the capacitor.

[0043] 17. The support system according to any one of paragraphs 13 to 16, wherein the control unit is configured to monitor the frequency of impedance changes at the inductive receiver.

[0044] 18. A support configured for fluid dynamics monitoring, the support comprising: The stent body is designed and configured to be inserted into the body cavity of a subject, and the stent body integrally forms a sensor and a capacitor, wherein the sensor and the capacitor form an LC circuit.

[0045] 19. The bracket according to paragraph 18, wherein the bracket body comprises: Internal conductive layer External conductive layer, and An insulating layer is located between the inner conductive layer and the outer conductive layer. The inner conductive layer and the outer conductive layer, together with the insulating layer, form the capacitor. One of the inner conductive layer and the outer conductive layer forms the sensor receiver.

[0046] 20. The bracket according to any one of paragraphs 18 or 19, the bracket being combined with a portable transceiver, the portable transceiver including an inductive transmitter and a control unit configured to monitor the frequency of impedance changes at the inductive receiver.

[0047] It should be understood that the various aspects disclosed herein can be combined with combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the example, certain actions or events of any of the processes or methods described herein may be performed in a different order, or may be completely added, combined, or omitted (e.g., performing these techniques may not require all the described actions or events). Furthermore, although for clarity some aspects of this disclosure are described as being performed by a single module or unit, it should be understood that the techniques of this disclosure can be performed by combinations of units or modules associated with, for example, a medical device.

[0048] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may include a non-transitory computer-readable medium that corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that is accessible by a computer).

[0049] Instructions can be executed by one or more processors (such as one or more digital signal processors (DSPs)), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Therefore, the term "processor" as used herein can refer to any of the foregoing structures or any other physical structures suitable for implementing the described techniques. Furthermore, these techniques can be fully implemented in one or more circuit or logic elements.

Claims

1. A support configured for fluid dynamics monitoring, the support comprising: A stent body, designed and configured to be inserted into a body cavity of a subject, the stent body comprising: Internal conductive layer External conductive layer, and An insulating layer is located between the inner conductive layer and the outer conductive layer. The inner conductive layer, the outer conductive layer, and the insulating layer together form a capacitor for use in fluid dynamics monitoring.

2. The bracket according to claim 1, wherein one of the inner conductive layer and the outer conductive layer forms a sensor receiver, wherein the capacitor and the sensor receiver form a bracket circuit, and the sensor receiver is configured to be inductively coupled to a remote inductive transmitter to sense current within the bracket circuit.

3. The bracket according to claim 2, wherein the internal conductive layer forms the sensor receiver.

4. The support according to claim 3, wherein the outer conductive layer is a structural layer that provides structure and support for the support body to suitably serve as a support.

5. The bracket according to any one of claims 1 to 4, wherein the bracket body is formed of bracket conductors formed as a continuous sine curve.

6. The stent according to any one of claims 1 to 5, wherein the stent body is expandable and configured to conform to the lesion in the blood vessel.

7. The bracket of claim 2, wherein the bracket is combined with a portable transceiver, the portable transceiver including the inductive transmitter and a control unit configured to monitor the frequency of impedance changes at the inductive receiver.

8. The stent according to any one of claims 1 to 7, wherein the internal conductive layer comprises at least one of gold and platinum.

9. The bracket according to any one of claims 1 to 8, wherein the outer conductive layer comprises a nickel-cobalt alloy.

10. The bracket according to any one of claims 1 to 9, wherein the insulating layer comprises ceramic.

11. The support according to any one of claims 1 to 10, wherein the support body further comprises an external electrical insulating layer surrounding the external conductive layer.

12. A support system configured for fluid dynamics monitoring, the support system comprising: A stent, configured for implantation into a subject's body cavity, includes a stent lead with a conductive layer shaped as a continuous sinusoidal curve to form a sensor receiver. A transceiver including an inductive transmitter and a control unit, wherein the inductive transmitter is configured to inductively couple with the inductive receiver to induce current within the support conductor.

13. A support configured for fluid dynamics monitoring, the support comprising: The stent body is designed and configured to be inserted into the body cavity of a subject, and the stent body integrally forms a sensor and a capacitor, wherein the sensor and the capacitor form an LRC circuit.

14. The bracket according to claim 13, wherein the bracket body comprises: Internal conductive layer External conductive layer, and An insulating layer is located between the inner conductive layer and the outer conductive layer. The inner conductive layer and the outer conductive layer, together with the insulating layer, form the capacitor. One of the inner conductive layer and the outer conductive layer forms the sensor receiver.

15. The bracket according to any one of claims 13 or 14, wherein the bracket is combined with a portable transceiver, the portable transceiver including an inductive transmitter and a control unit configured to monitor the frequency of impedance changes at the inductive receiver.

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